It is known to make a connection via a connector in order to supply electric power to a surface of a board on which surface a component is mounted from a side of a surface opposite to the surface. For example, an LED board on which an LED device is mounted is provided in a light source unit which is built in an LED light bulb. Electric power is supplied to the LED board from a circuit board which is arranged on a side opposite to a surface on which the LED device is mounted, that is, a side of a bottom surface. For example, a first connector is soldered to a top surface of the LED board. Lead wires for supplying electric power extend from the side of the bottom surface of the LED board, and a second connector to be engaged with the first connector is connected to tips of the lead wires. In assembling the light source unit, the lead wires are gone through a gap and/or an opening of the LED board to be routed from the side of the bottom surface to the side of the top surface of the LED board, and the second connector on the tips of the lead wires is to be engaged with the first connector arranged on the top surface of the LED board.
Here, in order to simplify or mechanize the assembly work, it is conceivable to make an electrical connection without using lead wires. For example, Japanese Patent Publication JP 2002-246085A illustrates a bottom entry type connector which is inserted into an opening provided in a board from one surface side of the opening. The bottom entry type connector includes a reinforcement metal member having an elastic arm to engage with the board.
Japanese Patent Publication JP 2005-285352A also illustrates a bottom entry type connector. The bottom entry type connector includes a housing, plural lead terminals which are fixed to the housing by press-fitting and a reinforcement metal member. A holding block is provided in the housing. In addition, the reinforcement metal member attached to the housing includes a supporting piece. The plural lead terminals are arranged to make contact with the board or approach the board in a state in which the bottom entry type connector is coupled with the board. The lead terminals are soldered to the board supported by the supporting piece.
However, in the bottom entry type connector of Japanese Patent Publication JP 2002-246085A, soldering of the reinforcement member itself is essential in order to prevent floating from the board. In addition, the bottom entry type connector of Japanese Patent Publication JP 2005-285352A requires soldering the plural lead terminals. If all of the plural lead terminals are not soldered, a part of the lead terminals separates from the board, leading to electrical discontinuity failure.